There are a number of medical procedures in which fluid is permanently or temporarily delivered to a target site for medical treatment, diagnosis, and/or monitoring. In some of these procedures, medical professionals benefit from knowing the pressure at which the fluid is delivered to the target site. One such well-known procedure is an angioplasty procedure in which a balloon catheter is inserted into a blocked artery to be treated. Once the balloon catheter is in place, a balloon of the catheter is then inflated and deflated in one or more cycles to open the blocked artery and restore adequate blood flow through the artery. In this instance, pressure is monitored to ensure that the balloon is not under-inflated or over-inflated.
A fluid delivery device that has been found useful in monitoring pressure during an angioplasty is shown in U.S. Pat. No. 5,385,549 to Lampropoulus et al. The device of Lampropoulus et al. includes a housing defining a fluid chamber for storing the fluid and a plunger for sliding in the fluid chamber to discharge the fluid from the fluid chamber to the balloon catheter. The plunger is threaded such that an engagement mechanism can lock to threads on the plunger to restrict movement of the plunger to solely rotational movement. This provides controlled discharge of the fluid into the balloon catheter. The device also includes a pressure sensor for sensing a pressure of the fluid in the fluid chamber and a controller in communication with the pressure sensor to determine the value of the pressure in the fluid chamber. A display is in communication with the controller to display the value of the pressure. In one embodiment, the display may be located on the housing.
Another relatively new procedure that requires the delivery of fluid to a target site for isolating or diagnosing the cause of back pain is discography. Back pain can have a variety of causes. One known culprit is damaged or injured intervertebral discs. Intervertebral discs can be broadly described as fibrocartilage disposed between adjacent vertebrae of the spine. The fibrocartilage acts as a pad and supports the adjacent vertebrae. When an intervertebral disc is damaged or injured, back pain can result at least in part to pressure being applied to the intervertebral disc. Discography can be used to isolate damaged intervertebral discs.
During discography, a needle is inserted into an intervertebral disc suspected of causing the back pain and a contrast medium is injected into the disc through the needle. Using fluoroscopy, the physician can determine whether the contrast medium is properly positioned within the nucleus of the disc to get an idea about the health of the disc. If the disc is healthy, the contrast medium will stay in the nucleus. If the disc is damaged or degenerated, the contrast medium can spread easily throughout the disc. If the disc is ruptured, the contrast medium can actually discharge out of the nucleus. During the procedure, the patient is asked to respond if any pain is experienced, especially pain that mimics the condition that the patient is complaining of. The patient lets the physician know that there is pain and the level of pain by telling the physician the amount of pain experienced on a scale of 1 to 10.
Early discography procedures only measured a single factor, namely the level of pain response of the patient. However, improvements to this original procedure have been made. For instance, in U.S. Patent Application Publication No. 2004/0193045 to Scarborough et al., a fluid delivery device is described for use in discography that monitors both pressure and volume of fluid being delivered to the intervertebral disc. Other prior art devices used in angioplasty procedures, such as the device in Lampropoulus et al., only monitor pressure. Scarborough et al. teaches that information regarding both pressure and volume can be correlated with the pain experienced by the patient to better diagnose the condition of the disc being evaluated.
The fluid delivery device of Scarborough et al., however, is not designed to be lightweight, hand-held, and placed within the sterile field during use. In fact, the fluid delivery device of Scarborough et al. utilizes a motor-driven plunger (adding weight to the device) to drive the fluid from a fluid chamber to the intervertebral disc. Scarborough et al. also does not provide for the wireless transfer of data from the fluid delivery device in the sterile field to an external device outside of the sterile field and Scarborough et al. does not provide a fluid delivery device that reduces false pain indications, e.g., patients signaling pain when no actual pain is experienced.
Therefore, there remains a need in the art for a lightweight, hand-held device that is capable of delivering fluid to a suspect disc while monitoring fluid pressure and a volume of the fluid delivered. Finally, there is a need in the art for a fluid delivery device that is configured for transmitting data from the fluid delivery device in the sterile field to an external device outside of the sterile field.